1. Field of the Invention
The present invention relates to an ultraviolet-ray irradiation apparatus for sterilization of a liquid or sludgy substance to be sterilized.
2. Description of the Related Art
Generally, ultraviolet rays are radiated onto a liquid or sludgy substance in order to sterilize the liquid or sludgy substance. However, since uniform irradiation is difficult to achieve, reliable sterilization is difficult.
An object of the present invention is to provide an ultraviolet-ray irradiator apparatus for sterilization which can uniformly and reliably radiate ultraviolet rays onto a liquid or sludgy substance in order to sterilize the substance in a safe and reliable manner.
In order to achieve the above object, the present invention provides an ultraviolet-ray irradiation apparatus for sterilization of a liquid or sludgy substance to be sterilized, comprising:
a double-wall ultraviolet-emission tube having an outer tube and a transparent, hollow inner tube permitting passage of ultraviolet rays;
a static mixer disposed within the inner tube;
a feeding unit for causing a liquid or sludgy substance to be sterilized to pass through the inner tube; and
an ultraviolet emission control unit for controlling emission of ultraviolet rays from the ultraviolet-emission tube.
According to the present invention, a double-wall ultraviolet-emission tube is employed, and a static mixer is disposed within a hollow inner tube located at the center of the ultraviolet-emission tube. A substance to be sterilized is caused to pass through the inner tube while being mixed by division, replacement, and superposition effects induced by the static mixer as well as being irradiated with ultraviolet rays through the entire outer circumferential surface of the inner tube. Therefore, ultraviolet rays can be radiated directly onto the substance to be sterilized in a close space, so that ultraviolet rays can be radiated onto the substance more uniformly as compared with a conventional scheme in which ultraviolet rays are radiated onto a substance through a thin separation wall.
In the ultraviolet-ray irradiation apparatus, an ultraviolet-ray-reflecting layer is preferably formed on an inner or outer surface of the outer tube of the double-wall ultraviolet-emission tube. In this case, ultraviolet rays can be efficiently radiated into the interior of the inner tube containing the static mixer.
The ultraviolet-ray irradiation apparatus preferably comprises temperature control means for maintaining the double-wall ultraviolet-emission tube at a predetermined temperature. In this case, the sterilization efficiency can be improved.